On Sunday at the world's richest football club, no fans could be spotted with tea-towels on their heads, but delirium lingers on. It remains surreal to read in the programme at a Manchester City match against Liverpool that it was: "The first home game for our new owners, led by His Highness Sheikh Mansour bin Zayed Al Nahyan, represented by our new chairman, His Excellency Khaldoon Al Mubarak."

With City 2-0 up before Liverpool's masterly fightback, City's fans launched into "We're not really here" - though not in disbelief at seeing Robinho in a sky blue shirt now; the anthem was minted during City's season in the old Division Two 10 years ago by fans finding themselves on terraces at clubs like Macclesfield and York. The fans' immovable loyalty in that third-flight season cemented City's status as a big club and legitimised the local council's decision to hand City the new publicly funded stadium after the 2002 Commonwealth Games, and those two factors made City, for all its unpredictability, eminently desirable to buy.

Since the hysteria fired by Sulaiman Al Fahim, Sheikh Mansour's dealmaker, bragging of "very deep pockets" and talking fantasy football, a more respectful tone is marking City's new era. In an open letter to "fellow Manchester City fans", Sheikh Mansour stressed loyalty to the manager, Mark Hughes, an understanding that "it takes time to build a team", the importance of the academy and homegrown players, an appreciation of City's history and a commitment to the community work the club's staff do in some of Manchester's grim neighbourhoods.

The letter emphasised that although Sheikh Mansour is a member of Abu Dhabi's ruling dynasty, he has bought City "in a private capacity", part of his "strategy to hold a wide portfolio of business investments". Few, though, doubt that the acquisition of a major Premier League club is part of the broader moves to enhance the national appeal of Abu Dhabi itself.

A central figure working on the City takeover for Mansour, alongside Khaldoon, has been Simon Pearce, an English expatriate who is the strategic communications director of the Executive Affairs Authority, a policy arm of the Abu Dhabi government.

In November 2007 Pearce, who is thought certain to join the City board, oversaw a new campaign to attract tourism and business partners to the emirate, launching a corporate brand for Abu Dhabi itself. The Office of the Brand of Abu Dhabi emphasises above all, and in detail down to the livery of taxis, that the emirate should be synonymous with: "Respect, for heritage, family, culture and tradition, for the environment and business, and above all, respect for each other."

The brand also stresses continuity for Sheikh Mansour's Al Nahyan dynasty, which has ruled Abu Dhabi since the 18th century: "Respect for leadership which has guided us over the lifetime of our emirate."

Insiders say it was Pearce who stepped in after Al Fahim's loadsamoney pronouncements and steered the tone back to dignity. The owners won friends at City particularly after Khaldoon spent time with the academy director, Jim Cassell, and on Sunday for inviting former greats into the directors box, including Tony Book and Colin Bell, who were not always given similar prominence by more local owners.

Dr Christopher Davidson of Durham University, author of a forthcoming book Abu Dhabi: Oil and Beyond, believes the City acquisition, following the sponsorship of Ferrari's formula one team and investment in top-end sports events and the arts, chimes with this promotion of Abu Dhabi. "Although the emirate has enormous wealth, they need good relations around the world, to invest their money profitably, and to attract western partners. It is a liberal Muslim country, and although there is no democracy, it is generally peaceful, with the Al Nahyans seen as spending their money generously." Davidson added, however, that "human rights are a blackspot" - Amnesty International has raised concerns about detention and treatment of migrant workers in the UAE. "Buying City presents a friendly image," he said, "that these are good guys, who like football, and Abu Dhabi is a safe place to visit and do business."

Sheikh Mansour, Davidson says, is up and coming among the 19 sons born to Sheikh Zayed bin Sultan Al Nahyan, Abu Dhabi's long-term ruler who died in 2004. Mansour's mother, Sheikha Fatima, had six sons, which made hers the ruling family's most influential "mother block" compared with Sheikh Zayed's other wives. Mansour's influence has grown - he chairs the International Petroleum Investment Company, one of the larger sovereign wealth funds.

The family's wealth, indistinguishable with that of the emirate, is almost limitless, with a round $1tn estimated in overseas assets alone. Manchester City is a tiny sliver of that, but bigger than almost anything in terms of publicity, hence the care being taken now to strike the right tone.

Neither side has confirmed officially the final price paid by Sheikh Mansour, but informed sources say the total for the club and its debts was close to the originally reported £210m. Thaksin Shinawatra is understood to have made a £20m profit on the £21.5m he paid for the club. So, with Mansour having paid just over £40m for the club itself, that leaves £170m of the purchase price made up of City's debts. Companies House documents indicate that Thaksin had £45.3m in loans outstanding personally. According to their most recent accounts, City owed £41m in loan notes, a further £42.4m provided for future stadium rent to the council, and City borrowed £25m from Standard Bank in July this year. Those borrowings, including Thaksin's, add up to £154m, leaving around £16m other debts.

Thaksin, now honorary president of City, stopped funding the club with £800m of his assets frozen and criminal proceedings continuing in Thailand. Last month the Thai supreme court did not deliver a verdict as expected on the corruption charge against him, and has instead issued four arrest warrants for him to return. According to reports, he has applied for political asylum here.

Few at City doubt that Thaksin used the club in his political fight to boost his profile and enable him to return home freely. That failed, and he is now yesterday's man, even at Eastlands, supplanted by the reign of Al Nahyan.

In his superb book Manchester: A Football History, Gary James writes of City's beginnings that the club was established in 1880 by the rector's daughter at St Mark's Church, to provide poor, scrapping young lads with something wholesome to do in wretched east Manchester, the smoky side of the world's first industrial city. Now industry is gone and east Manchester's regeneration is based around the football stadium itself and new housing. Sheikh Mansour's bold purchase of the Manchester club happened just as the post-industrial economy, reliant on credit and consumption, was slumping into banking collapse.

For all the delight among City fans, there is clearly discomfort within the FA and football generally about so much wealth pouring into one club from a member of a country's government. City's takeover symbolises the wider phenomenon, of world financial power shifting from our credit-exhausted land to east Asia, where they actually make things, and the Middle East, where families who ruled for generations had the great good fortune to discover they were sitting on oil.

Cash for cachet

In the Abu Dhabi "Brand Briefing", Simon Pearce, the director of strategic communications for the emirate's Executive Affairs Authority and now a key figure at Manchester City, said "sponsorships or associations" should "epitomise Abu Dhabi". Sheikh Mansour's City purchase follows other landmark moves in prestigious sports events and the arts

Sheikh Mansour led the campaign for Abu Dhabi to host the Fifa Club World Cup in 2009 and 2010

In 2009 Abu Dhabi will host its first formula one grand prix

Mubadala Development Company, a government investment vehicle, sponsors Ferrari's formula one team

Khaldoon Al Mubarak, right, City's new chairman, is the chief executive of Mubadala and was instrumental in the Ferrari sponsorship and securing the grand prix

Abu Dhabi's Etihad Airways are now sponsoring Chelsea

The emirate is to spend a reported $1bn on a version of the Louvre art gallery, and is also building the Guggenheim Abu Dhabi museum